The present invention relates to improvements to snap-action closures. The problem of leakage in the conventional snap-action closures is overcome by providing a resilient seal comprising an elastic gel composition between the opening and the flexible panel (2) which deforms when the flexible panel (2) is closed to create a liquid-tight seal. In particular, the gap in the region of the closure hinge (7) is closed by the elastic flow of sealant material (9) where very little, if any, closing force is otherwise exerted.